Updated March 05, 2015.

Definition:

Hypertrophic cardiomyopathy is a fairly common heart problem, occurring in 1 in every 500 people, and is a common cause of sudden death in young athletes.

Hypertrophic cardiomyopathy makes it hard for the heart to work well, as the walls of the heart become thickened and stiff.

Unfortunately, children with hypertrophic cardiomyopathy usually don't have any symptoms or may have mild symptoms, such as occasional chest pain, weakness, palpitations, shortness of breath when exercising, or dizziness.

So, they may seem fine, but then collapse while exercising, competing in a sport, or just sitting.

The lack of symptoms make having a high index of suspicion important, which might include:

• a yearly pre-participation sports physical exam, although most children with hypertrophic cardiomyopathy have a normal physical exam. Some do have a heart murmur that your pediatrician may hear during the physical exam.
• regularly asking about possible symptoms of hypertrophic cardiomyopathy, such as weakness, fatigue, shortness of breath when exercising, palpitations (rapid or irregular heart beats), chest pain when exercising, dizziness, or syncope (passing out or fainting).
• a family history of hypertrophic cardiomyopathy or sudden death at a young age, especially before the age of 50. This is important because is some cases, hypertrophic cardiomyopathy can be genetic and inherited from other family members.
• routine ECG and echocardiography, which can detect hypertrophic cardiomyopathy, but which many experts think is too expensive and not cost effective to do routinely on all athletes.

Also Known As: HCM, hypertrophic obstructive cardiomyopathy (HOCM), idiopathic hypertrophic subaortic stenosis (IHSS), or asymmetric septal hypertrophy (ASH)

Alternate Spellings: HC

Examples: People with hypertrophic cardiomyopathy are sometimes misdiagnosed as having exercise-induced asthma since both conditions can cause shortness of breath during exercise.